ACQUISITIONS AND DISPOSITIONS OF ASSETS - Pro Forma Results (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pro Forma Information
Total revenues	$ 2,692,890	$ 2,720,735
Net Income	597,054	252,902
Net Income attributable to Sinclair Broadcast Group	$ 578,963	$ 247,441
Basic earnings per share attributable to Sinclair Broadcast Group (in dollars per share)	$ 5.80	$ 2.64
Diluted earnings per share attributable to Sinclair Broadcast Group (in dollars per share)	$ 5.74	$ 2.62